Garden School:

Garden School:
Teaching this week: Rose pruning (again!) and Clematis pruning

Tuesday, 18 October 2016

Garden Hygiene Part I: Tools

Coincidence is an interesting thing, isn't it? I had an email the other day from Corine *waves enthusiastically* asking about reducing the risk of spreading diseases/pests from one garden to another.

As a Professional Gardener, obviously this is very important to me, and the coincidence occurs because I have been researching into the sticky (literally!) question of tool hygiene, with particular reference to fruit and rose pruning.

It's one of those issues on which everyone has an opinion, but virtually all of them are actually wrong.  More of that later.

Firstly I'd like to split the question into three parts - this one deals with general hygiene for gardeners, Part Two will deal with moving plants, and the third part will cover the thorny question of hygiene relating to fruit and rose pruning (did you see what I did there? "thorny" question, regarding roses? No? Oh well).

And within each part, the first point to make is the difference between "cleaning" - which means physically removing the dirt/germs/bugs - and "disinfecting" which means killing the germs.

Right, general garden hygiene, then. If you ("one") work in more than one garden, it makes sense to take some basic precautions, and that means not transferring mud/dirt/debris/bugs from one garden to another: this is "cleaning". I am assuming that you, like me, have your own tools: if you use the Clients' tools (something of which I disapprove, for several reasons!) then obviously you don't need to bother too much, although it is polite - if nothing else - to leave tools cleaner than you found them.

During the last outbreak of foot-and-mouth, things were much more serious, and I chose to have two sets of tools and footwear, swapping them over at lunchtimes, and decontaminating (ie cleaning and disinfecting) both sets every evening. I found this was more efficient than trying to rush through the cleaning during my lunch break.

Phew, it was hard work!

Was it necessary? Well, probably not, but I thought it was better to be safe than sorry.

Since then, we have reduced to Hort-Com 3, as it were, and I went back to my normal routine of merely "cleaning" tools and boots off at the end of each session - I should say that I mostly do only two jobs a day, but if you do three or more, then all comments will obviously relate to each gap - and after working in the one garden which I knew to have honey fungus, I was particularly careful about cleaning tools and boots thoroughly.

"Cleaning" means scraping off all the mud/dirt/debris. Starting with the larger tools, ie fork, spade, and trowel, I use a smaller tool, usually the good ole' Daisy Grubber, then a wipe over with a gloved hand. If your tools are ancient, rusted and pitted, then you are never going to get them clean, so buy some nice modern lighter weight stainless steel ones!

Next is cleaning the boots, again with the Daisy Grubber: turn up one foot at a time and scrape through and through the cleats (the knobbles on the sole) then once vertically all round the edge. It's always easier with one hand than the other, but learn to do it with both hands, although not at the same time, obviously! Remove any remaining soil with a stiff brush or a damp cloth.

Once everything else is done, the Daisy Grubber gets wiped on the grass then on the glove, and finally the gloves get brushed together vigorously to shake off the loose stuff, then put aside to dry.

This may sound like a lot of faff, but you can make it easier for yourself by being efficient: try to do all the digging for each session in one go, then clean the fork/spade just once. If it's a wet sort of day, I'll usually leave the cleaned tool standing out to dry, then wipe it over with a glove just before putting it away, as it's often easier to remove the last dribs and drabs of soil once it has dried out.

As for the boots, I plan out my work so that I stop working on the soil about 20 minutes before the end of the session, to give me time to clean out the soles of my boots - as described above, with the Daisy Grubber - then I can walk about on their grass to get them perfectly clean before I leave. This might sound a bit mean, but the principle is that their earth (and any nematodes, disease etc it may carry) stays within their garden: and I don't waste that last 20 minutes, I use it to do the final wheelbarrow emptying run, collecting up of tools etc then some easy light work such as deadheading or weeding while standing on the grass, ie not treading on the borders again, to keep the boots clean. I find that ten minutes or so of walking on wet grass is enough to get all the mud off, and this removes the need for stiff brushes etc. If the grass is dry, then generally speaking so is the soil, so it's not clinging to the boots in the same way, and I can usually find an area of grass that is out of sight, so I can "scrub" my boots across it a few times.

On wet days, once the boots are clean, even a short walk across hard standing will allow them to dry, so by the time I have done my paperwork and returned to my car, they are clean and dry and I don't need to worry about transferring anything nasty to my car mats.

All that leaves, for the end of the session, is the Daisy Grubber and the gloves: and I have so many pairs of gloves on the go that it's very simple to drop the "dirty" pair into a plastic bag to be taken home in quarantine, until they can be spread out to dry.  See? Not such a chore, after all.

Now, moving onto specific garden pathogens such as honey fungus and phytophthora: the former has air-borne spores, the latter has some types which are air-borne, but is mostly spread by water-borne spores.

Honey Fungus:

Some basic research into honey fungus reveals that virtually all gardens have the spores present: spores have been found up to five miles high in the atmosphere, so they pretty well blanket the entire country. Honey fungus is really only a problem with susceptible plants, by which I mean plants which are sickly, stressed, ailing etc. Strong healthy plants are not bothered by the presence of honey fungus: which stands to reason really, otherwise anyone who found honey fungus in their garden would shortly have a totally barren dustbowl instead of a garden, and that is clearly not the case.

So there is not much point in trying to disinfect boots and tools to prevent that sort of disease.


This particular blight spreads mainly by 1) water and 2) human activities. Rain and irrigation wash the spores off infected plants and down into the soil: and boots, tractor tyres, animal paws etc pick up damp soil containing these washed-down spores, and trample them from one place to another.  Thus, it spreads.

So, there is every reason for cleaning soil - mud, dirt, debris - off your tools and boots between sites.

As an aside, when I get in my car I have a pack of wet-wipes, and use a couple of them to remove excess mud from my legs and arms: not that I seriously think that any germs would be transmitted that way, but more to keep my car relatively clean! Don't buy expensive Wet Wipes at £1 for a tiny pack of 10:  go to your supermarket's baby section, and buy the cheapest own-brand wipes. They are more like 50p for a pack of 80 or more, so you can be generous with them. On hot days, they are also perfect for wiping a sweaty face and neck! They are not particularly sound on the recycling front - but I stuff my not-very-dirty used ones into the cupholder in my car, and as they dry out they get used again for cleaning bird poo off the windscreen and bodywork, before finally being put in the bin.

Getting back to Garden Hygiene, as far as sensible daily hygiene goes, the trick is definitely to Let Things Dry, and this is the point of doing the detailed mud removal.  Most germs/bacteria/bugs die without a damp environment, so if you can allow tools and boots to dry thoroughly between use, you are unlikely to be moving contaminants around. So it's well worth buying extra boots and gloves, so you can change at mid-day: and it makes them last longer as well, if you can give them a rest and let them dry out properly between wearings.

So, in answer to Corinne's question about inter-garden hygiene, the answer is to remove as much of the loose mud and debris as you can: wipe off the rest: allow tools and boots to dry between sessions, and don't allow a build-up of soil.

Part Two will deal with moving plants, and then on Part Three we get to the knotty problem of disinfecting tools: exciting stuff, eh?!